Pneumatically operated fastener positioning and driving machine



Feb. 1, 1966 c. E. L. CROOKS 5 PNEUMATICALLY OPERATED FASTENERPOSITIONING AND DRIVING MACHINE 2 Sheets-Sheet 1 Filed July 24, 1963 lNV ENTOR.

/ A 'TTORNE YS Feb. 1, 1966 c E c oo s 3,232,511

PNEUMATICALLY dPEIIATED FASTENER POSITIONING AND DRIVING MACHINE FiledJuly 24, 1963 2 Sheets-Sheet 2 I NVENTOR.

C zaz leafii. 6 1 00145 A TT( )1? NE YS United States Patent Office3,232,511 PNEUMATICALLY OPERATED FASTENER POSI- TIONING AND DRIVINGMACHINE Charles E. L. Crooks, Barrington Hills, 111., assignor, by mesneassignments, to Swingfast, Inc., Long Island City, N.Y., a corporationof New York Filed July 24, 1963, Ser. No. 297,321 8 Claims. (Cl.227-130) The present invention relates to improvements in fastenerdriving machines and more particularly concerns a pneumatically operatedmachine especially adapted for driving nails carried on supportingstrips of material.

For convenience in handling round headed nails for driving in a drivingmachine equipped with nail guiding means and a driving plunger, it hasbeen proposed to assemble the nails in uniformly spaced coextensiveparallel relation by suitable connecting and supporting means. In oneexample of such connecting and supporting means, flat elongatedrelatively narrow strips of a suitable sheet material are employed.Conveniently such strip material has been a low cost synthetic plasticmaterial. Suitably spaced holes in a longitudinal row in the stripcarrier have the nails engaged therethrough in spaced parallelcoextensive relation. The nails are then supported in the magazine ofthe driving machine on the carrying strip.

One of the problems encountered in such a mode of supplying nails formachine driving resides in that because of the thinness and thusflexibility of the carrying strip for the nails, a spring biased pusherin the magazine of the machine is impractical due to tendency of thepusher especially when fully retracted and thus substantially maxi-mumspring loaded to exert suflicient pressure on the strip carried nails tocause buckling of the carrying strip. It is to th solving of thisproblem of feeding strip nails in a driving machine to which the presentinvention is, in the main, directed.

An important object of the present invention is to provide a new andimproved pneumatically operated strip nail driving machine having anovel nail feeding device.

Another object of the invention is to provide new and improvedpneumatically operated fastener feeding means for driving machines.

A further object of the invention is to provide new and improved meansfor accommodating strip nails in a fastener driving machine.

Still another object of the invention is to provide new and improvedpneumatically operated fastener feeding means for pneumatically operateddriving machines.

Other objects, features and advantages of the present invention will bereadily apparent from the following detailed description of certainpreferred embodiments thereof taken in conjunction with the accompanyingdrawings, in which:

FIGURE 1 is a side elevational view, partly broken away and in sectionof a pneumatically operated fastener driving machine embodying featuresof the invention;

FIGURE 2 is an enlarged fragmentary sectional elevational detail viewtaken substantially on the line IIII of FIGURE 1;

FIGURE 3 is a view similar to FIGURE 2 but showing the nail advancingmeans in a nail advancing position;

FIGURE 4 is an enlarged fragmentary front elevational view showing thenose structure of the machine of FIGURE 1;

FIGURE 5 is a substantially larger fragmentary sectioual elevation viewof the hinge and biasing means for the nail advancing finger of thedevice;

FIGURE 6 is a fragmentary sectional elevational view 3,232,511 PatentedFeb. 1, 1966 of a modified arrangement of the nail feeding device, and

FIGURE 7 is a fragmentary sectional elevational view showing a modifiedarrangement utilizing exhaust air for actuating the nail feeding device.

A representative fastener driving machine 10 as shown in FIGURE 1includes a front driving head 11 having extending rea nwardly therefroma handle 12 and affording a machine body which may in a practicalarrange: ment, comprise a casting. On the lower end of the body providedby the driving head 11 and the handle 12 is a fastener supporting andsupply magazine structure 13 which may, if preferred, comprise a unitaryportion of the body casting, but is in this instance disclosed as aseparable elongated hollow bar-like mem ber detachably secured as bymeans of screws 14 to the lower end of the head 11 and the rear endportion of the handle 12. Such detachable arrangement of the magazinepermits selec tive use with the machine body of magazine for fastenersof different sizes and types.

In the present instance, construction of the magazine 13 is such as toadapt it for handling nails 15 (FIGS. 1-4) having round heads 17 andcarried in spaced parallel coextensive relation on at least one and inthis instance two carrying strips 18. In a preferred form, thesecarrying strips comprise thin, self-sustaining, narrow elongated stripsof synthetic plastic material of an inexpensive grade such that it mayserve as a low cost disposable item. The strips 18 are provided withsuitable series of longitudinally spaced, and preferably uniformlyspaced, aligned nail receiving holes 19 of a diameter to receive theshanks of the nails 15 reasonably snugly so as to avoid unintentionaldisplacement of the nails from the strips. One of the carrying strips 18is located immediately adjacent to the nail heads 17 and the other ofthe strips is located in desirable spaced parallel relation thereto,whereby to have a substantial intermediate length of the nail shanks between the two strips and to hold the nails in fixed parallel relationfor accurate feeding and driving.

Within the magazine 13 a longitudinally extending pair of opposed spacedtrack shoulder ribs 20 providing coplanar upwardly facing tracks, onopposite sides of a clearance slot 21, for supporting the carrying strip18 nearest the nail heads 17 in longitudinally slidable relation withthe shanks of the nails 15 clearing through the slot 21 which is alignedwith and affords a guideway toward a driving nose 22. This nosecomprises an assembly of a facing plate 23 abutting the front end of themagazine member 13 and a front plate 24 abutting the forward face of thebacking plate. Screws 25 secure the nose plates in assembled relationagainst the magazine member, the front plate 24 having keyhole openings27 to facilitate quick removal and replacement of the front plate. Adoorway slot 28 through the facing plate 23 is aligned with the trackguide slot 21 and with a longitudinally extending rearwardly openingdriveway groove 29 in the front plate having its exit end openingthrough the tip of the nose assembly 22 and its opposite end alignedwith the base end of the driving head 11 for driving reciprocation of adriver blade 30 for successively driving the nails 15 from and throughthe carrier strips 18 and into a surface to receive the nails. In sodriving the nails, the strips 18 are sufficiently flexibly yieldableabout the nail engaging openings 19 to pass the nail heads 17therethrough under the driving thrust of the driver 30.

As best seen in FIGURE 4, the facing plate 23 and the front plate 24 areprovided with aligned clearance openings 31 therethrough spacedlongitudinally along the driveway 29 for clearing the expended carrierstrips 18 therethrough. These clearance openings are large enough toavoid binding of the carrier strips in passing .therethrough shouldthere be some distortion of the strips as a result of passage of thedriver blade therethrough, but the upper edges defining the openings aresubstantially aligned with the positions assumed by the carrier strips18 as they are fed with the nails through the magazine, so that suchupper edges serve as stripper edges to hold the strips against followingthe driving blade as it is retracted. Along their lower edges, theclearance openings31 have respective recesses 32 to assure positiveclearance of downwardly displaced material about the nail openings 19 toavoid catching on the plates. On the other hand, the edges defining theopenings at each side of each of the clearance recesses 32 provide stopsagainst overtravel of the strips in the direction of nail drive.

Actuation of the driver 30 is effected by pneumatic motor meansincluding a piston 33 to which the driver is attached and which isreciprocable in a cylinder 34 within the driving head 11. In the presentinstance the pneumatic motor is of the so-called explosion type whereinthe upper end of the cylinder 34 is exposed to a reservoir 35 whichincludes at least a portion of the interior of the head 11 and thehandle 12 and to which compressed air is delivered as by means of aconduit 37 leading from 'a suitable source and attached to the handle12. In operation air is maintained under substantially constant pressurewithin the reservoir 35 and is normally prevented from entering thecylinder 34 by means of a control valve 38 of the poppet typereciprocably mounted within an inverted cup-shaped closure cap 39 andhaving a hollow stem 40 through which air above the piston 33 is adaptedto be exhausted to one or more exhaust openings 41 in the crown of thecap 39. A starter spring 35a supplements compressed air delivered to theupper side of the valve member 38, acting more or less like a diaphragm,to force the valve into closing relation on the end of the cylinder 34in opposition to air pressure on the margin of the valve member exposedto the reservoir 35 beyond the end of the cylinder, substantially asshown.

Compressed air is delivered to the chamber on the upper side of thecontrol valve 38 and is exhausted or bled off from such chamber througha passage 42 under the control of a valve 43 having a plunger 44arranged to be actuated by a trigger lever 45. In the non-drivingcondition of the machine, pressure air enters through a port 47 past thevalve 43 into the passage 42 and thus acts on the upper side of thevalve 38 to hold it in cylinder closing position. When the trigger isdepressed, the valve 43 is unseated and air over the valve 38 exhaustsor is bled off by way of the passage 42 past the valve 43 and the valvestem 44 and out through an exhaust passage 48. Instantly upon openingthe bleed off to atmosphere, by depressing the trigger 45, the controlvalve 38 is unseated by the air pressure in the reservoir 35, the valvestem 49 closes the exhaust ports 41 and the piston 33 is driven in afastener driving stroke. Upon release of the trigger 45, the motorsystem is returned to the starting or load position read for firing andthe piston 33 is returned to starting position in any suitable manner asby air pressure in known manner.

According to the present invention, pneumatically actuated means areprovided coordinated in operation with the pneumatic motor for feedingthe nail strip by successive nail increments wherein the nails areserially advanced into position in the driveway 29 coordinated with thereturn strokes of the driver 30. In one exemplary embodiment, apneumatic feed device 49 is mounted on one side of the magazinestructure 13 and is pneumatically controlled through the trigger 45substantially coincident with control of the pneumatic driving motor,and more particularly control of the motor control poppet valve 38. Tothis end, the nail feed device 49 comprises a suitable housing 50 havingsuitable means such as a flange 51 for attachment thereof as by means ofscrews 52 to the preferred, in this instance, right hand, side of themagazine structure 13 and with the body of the housing 50 at leastpartially accommodated within a suitable recess 53 in the supportingwall of the magazine.

Within a cylinder 54 in the housing 50 is reciprocable a plunger piston55 having a stem or rod 57 projecting through the forward end of thehousing and carrying a nail advancing feed finger 58. In this instance,the piston 55 is oriented to operate on a longitudinal axissubstantially parallel to the axis of the magazine 13 and at anelevation relative to the magazine locating the piston and the finger 58between the planes of nail carrying strips 18 as loaded into themagazine. From the front end portion of the piston rod 47, the finger 58extends at an angle inwardly and forwardly to a length which brings itsfree end as a pusher tip into position behind one of the spaced nails 15in the nail strip. For most efficient operation and to avoid anytendency toward buckling of the thin carrying strips 18 from poweredthrust of the feed finger 58, disposition of the feed assembly is suchthat in the retracted or backed-off relation of the feed plunger pistonand finger, as shown in FIGURE 2, the nail-engaging forward tip of thefinger is disposed immediately back of the shank of the nail 15 which isnearest the doorway slot 28 and next to be fed into the driveway groove29, so that in the forward driven thrust of the feed finger, such nailwill be advanced into the driveway groove and the nail strip advanced bya nail increment.

In order to clear the generally obliquely angular disposition of thefeed finger 58, the edge portion of the facing plate 23 at that side ofthe doorway slot 28 nearest the feed finger is provided with a clearancecut back recess 59. Aligned with and comprising substantially anextension of the recess 59 is a recess 60 in the adjacent portion of thefront plate 24 alongside the rear portion of the driveway groove 29 andwhich is preferably of a curved, ramp-like formation leading into thenailreceiving bottom or base portion of the driveway groove and wherebyto guide the tip of the feed finger 58 positively and smoothly into thedriveway groove for complete feeding of the nail to be driven into thedriveway should there be any tendency for the driving tip portion of thefinger to be slightly misaligned or at least not as nearly aspracticable directly behind the nail being thrust forwardly thereby.Further, the ramp-like formation of the aligned surfaces of the recesses59 and 60 affords a means for maintaining the feed finger 58substantially against canting about its axis, whereby its driving tipportion which is preferably of substantial width in a plane generallyparallel to the axes of the nails 15 to afford eflicient thrust bearingalong a substantial length of the shank of the engaged nail, althoughfor working clearance accommodation purposes the driving tip end portionmust be of substantial thinness, as shown.

In order to enable the feed finger 58 not only to engage eflicientlywith the nail to be driven throughout the driving stroke of the feeddevice, but also to clear past the next to be driven nail on the returnstroke of the feed finger, an articulated connection is provided betweenthe piston rod 57 and the feed finger 58. For this purpose the forwardend portion of the piston rod is provided with a tongue-like flattedportion 61 and the rear end portion of the feed finger 58 is bifurcatedto receive the lug or tongue 61 and to which the furcations arepivotally connected by a suitable pin 62 or the like. Normally the feedfinger 58 is biased about its pivotal connection to swing its feed tipend portion toward the nails 15 in the magazine. Since the range ofswinging movement of the finger need be only through a small are on theorder of about the diameter of the shanks of the nails 15, a convenientbiasing means comprises a short arcuate piece of spring wire 63 havingits opposite ends thrust respectively into a socket 64 in the tip of thetongue 61 and a socket 65 opening from a generally rearwardly facingopposing shoulder 67 on the feed finger between the furcations thereof.This will afford mild spring bias for the feed finger which is overcomewithout undue generally sideward and rearward thrust of the forward endportion of the feed finger as it slides past the nail which it engagesin the return or back-off stroke of the feed device.

A limit upon inward swinging of the feed finger 58 under the bias of thespring 63 is afforded by a limit shoulder 68 on the butt end portion ofthe finger between the furcations and Opposing the tip of the ear ortongue 61 adjacent its inner edge, as best seen in FIGURE 5. Thereby,possibly binding side pressure against the shank of the nail next behindthe nail to be engaged for feeding by the finger is avoided andsubstantially wear-free and easy feeding of many successive nail stripsis accomplished. However, during return stroke of the feed device theslight lateral, biased thrust of the feed finger against the nail to benext fed causes sufficient friction of the shank of such nail againstthe opposite wall defining the guide groove 21, taken together withother frictional resistances of the strip in the magazine 13 and thedriving nose 22, to avoid rearward dragging of the strip during suchreturn stroke of the feed device.

A guard for the feed finger 58 is afforded by a protective flangeportion 69 (FIGS. 2 and 3) outwardly alongside the clearance affordedfor the finger in the forward portion of the magazine structure 13. A-guard outwardly alongside the piston rod 57 and the connection with thefinger 58 is afforded by a forward protective flange extension 79 on theouter side of the housing 50. Preferably, there is a sighting andself-cleaning gap between the adjacent ends of the guard flanges 69 and70 through which proper functioning of the feed finger can be observed,and through which, also, debris particles such as may be dislodged fromthe carrier strips 18 during driving can readily displace.

Return stroke of the piston 55, and thereby the feed finger 58, iseffected herein by suitable means such as a coiied compression spring 71thrusting at one end against the forward side of the piston and at itsopposite end against the wall defining the front end of the housing 51'and closing the front end of the cylinder 54.

Forward, nail feeding stroke of the piston 55 and feed finger 58 iseffected pneumatically to afford a positive, rapid, powered thrust whichwill, even in rapid operation of the driving machine assure feeding andcentering of the nail to be driven in the driveway 29 aligned with thedriver 30. Conveniently compressed air for this purpose is derived fromthe control passage 42 through a suitable duct 72, conveniently in theform of a metal tube having one end tapped into the passage 42 through anipple and coupling assembly 73. At its opposite end the duct 72 isconnected by suitable means such as a nipple and connector assembly 74?to communicate with the rear end of the cylinder 54 behind the head ofthe piston 55. Through this arrangement, when compressed air is in thepassage 42 for pressurizing the control poppet valve 38 into closingposition relative to the motor cylinder 34, some of the compressed airis diverted or by-passed to the feed device cylinder to drive its motorcomprising the piston 55 to motivate the feed finger 58 in a feedstroke. This assures that when the driving motor of the machine is inthe ready or load condition, one of the nails will be in position withinthe driveway 29 to the driven. Since the feed finger 58 thus thrustspositively against the nail to be driven in the ready condition of themachine, such nail will not be displaced from driving position by anyinward or rearward pressure that may be exerted against the forwardlyprojecting portions of the extended nail carrying strips 18.

Simultaneously with actuation of the machine (often referred to asfiring of the air gun) by actuation of the trigger and thus the controlvalve 43 to shut the control passage 42 from the reservoir air sourceand to bleed such passage, for unbalancing the control poppet valve 38,bleed-off to atmosphere through the same bleed-off systom occurs inrespect to the cylinder 54 through the duct 72 and the feed piston 55and feed finger 58 are snapped into retracted position by the returnspring 71. As a result, a completely coordinated operation of thepneumatic feed device 49 and the driver actuating pneumatic motor isafforded.

Although the tapping of the combination air pressure supply and exhaustducts 72 into the poppet valve control passage 42 is preferred,alternatively such duct may be tapped into the exhaust passage systemabove the driving piston 33, substantially as shown in FIGURE 7. In suchevent, the end portion of the duct 72 remote from the feed device 49 isadapted to be connected as by means of a fitting 75 into a port 77 whichleads from the exhaust dome of the closure cap 39 instead of the exhaustports 41. Through such arrangement, the air exhausted from the cylinder34 by the retaining driving piston 33 will pass through the port 77 andthe duct 72 under sufficient compression of the returning piston todrive the feed motor piston 55 in a nail feeding stroke until the pistonat substantially the end of its feed stroke passes an exhaust port 78,such as shown in FIG. 6, opening through the Wall of the housing 50defining the cylinder 54 whereupon the air .is exhausted to atmosphere,thus relieving the driving piston of back pressure.

In another arrangement wherein the pneumatic feed device is motivated byexhaust air on return of the driving piston is depicted in FIGURE 6. Inthis arrangement the magazine 13, carrying the pneumatically operatedfeed device 49 which includes the feed finger 58 and which functions inevery respect like the modified arrangement of FIGURE 1 including theexhaust port 78, is associated with a fastener driving machine 10' ofthe type including a driving head portion 11 in which there is a drivingcylinder of the conventional type to which air from a reservoir 79 inthe handle 12' is controlled to pass to the top of the driving pistonthrough a delivery passage 80 when a valve 81 is unseated by the trigger45. In this arrangement, air from over the driving piston bleeds off toatmosphere past the stem of the valve 81 through a port 82 and a passage83 leading to the rear of the handle 12'. Feed drive of the feed device49 and more particularly the driving motor piston thereof occurs bydiverting the exhaust air from the exhaust passage 83 through the duct'72 which is connected by a suitable connector means 75' to the rear endof the passage 83 and leads the exhaust air into the rear end of thecylinder within the housing Ed, the air bleeding off to atmospherethrough the side port 78 when the feed piston has been driven to the endof its nail feeding stroke. 7 It will be understood that modificationsand variations may be effected without departing from the scope of thenovel concepts of the present invention.

I claim as my invention:

1. A fastener driving machine comprising a body having therein acompressed air reservoir,

a cylinder having an end exposed to the reservoir and a first controlvalve for normally closing said end of the cylinder,

a fastener driver having a piston reciprocable in said cylinder,

means for supplying fasteners into position to be driven by the driver,pneumatically operated feed means mounted on the machine for feeding thefasteners into position successively in the path of the driver, I

and a pneumatic system including a second control valve for controllingoperations of said first control valve for opening the same to exposethe driving piston to the pressure air in said reservoir and to controlfeeding operations of said feeding means, said pneumatic systemincluding a passage leading from said second control valve to said firstcontrol valve and a duct communicating between said passage and saidfeeding means.

2. A fastener driving machine as defined in claim 1, in which said ductis attached at one end to said feed means externally of the machine, anda coupling assembly is tapped into said passage and the conduit isconnected at its opposite end to said passage by means of said coupling.

3. A fastener driving machine including a magazine structure forsupporting a strip of nails carried in serially arranged spaced parallelcoextensive relation on a carryi-n-g strip,

a nose assembly providing a nail driveway and an ejection openingthrough which the nail carrying strip can be ejected,

a nail feed finger arranged to engage the succeeding nails to be drivenand move the same into said drivea pneumatic motor for actuating saidfinger including a plunger having an articulated connection with saidfinger,

said finger and plunger having opposed generally axially extendingsurfaces comprising in part stop shoulders limiting articulation of thefinger relative to the plunger in one direction,

said surfaces including portions which remain spaced apart in theshoulden'ng engagement of the shoulder portions and having springsockets therein,

and an end thrust biasing spring having end portions seated in saidsockets and biasing said feed finger in said one direction.

4. In a fastener driving machine including a driving head and a magazinestructure for fasteners with elongated shanks to be drivenlongitudinally from a driveway into which the fasteners are adapted tobe fed from the magazine structure,

said magazine structure having a recess accessible from one side of themagazine structure,

a fastener feeding unit including a housing mounted in said recess,

said magazine structure having an opening thereinto aligned with saidrecess and adjacent to said driveway to expose the shanks of fastenersin the magazine structure adjacent to the driveway,

a reciprocab-le fastener feeding member including a portion reciprocablyguided in said housing,

said feeding member having a fastener shank engaging tip portionprojecting through said opening,

and means for reciprocably actuating said feeding member to engage theshanks of and advance successive fasteners into said driveway.

5. A fastener driving machine as defined in claim 4, in which saidhousing and said magazine structure have guard flanges outwardlyadjacent to and protectively related to said fastener feeding member.

6. A fastener driving machine including a magazine for supporting astrip of nails comprising a series of spaced parallel nails and acarrying strip with which the nails are engaged,

means in the magazine providing a track on which the nail carrying stripis slidably supported with the nails extending in a plane generallynormal to the track,

a nose structure at one end of the track and providing a nail drivewayon an axis parallel to the axis of the nail shanks,

a fastener driver reciprocably operable in said driveway to drive thenails,

means for feeding the strip toward the driveway to position successivenails in the driveway to be driven by the driver,

said nose structure having an exit opening aligned with said track forejection of expended nail carrying strip,

said exit opening being defined adjacent to the driver by a stop surfacefor stripping the strip from the driver during retraction of the driver,

and said exit opening being defined by an opposite stop surface toretain the strip against following the driver during nail driving strokeand this stop surface having a recess therein for positive clearanceduring ejection of the strip of material thereon displaced incident todriving of fasteners from the strip.

'7. A pneumatic fastener driving machine including a fastener driverhaving a pneumatic motor comprising a cylinder and piston with means forexhausting air from the cylinder over the piston during return strokesof the piston,

reservoir means for supplying compressed air to drive the piston andthereby the driver,

means for controlling application of the compressed air to the piston,

a fastener magazine for supporting a supply of serially arrangedelongated shank type of fasteners to be driven by the driver,

said magazine having an opening at one side through which the fastenershanks are accessible,

pneumatically operated means mounted on the machine rearwardly adjacentto said opening and including a resiliently mounted feed fingerextending through the opening into engagement behind successive fastenershanks for feeding the fasteners from the magazine successively intoposition to be driven by the driver,

means normally urging the feeding means into a retracted position so asto clear said finger from the path of the driver,

and means connecting said air exhausting means with said feeding meansto supply the exhaust air under returning piston pressure to actuate thefeeding means in a feeding stroke.

8. In a fastener driving machine including a fastener magazine structureproviding a magazine track to support fasteners having elongated shanks,

:a nose structure having a fastener driveway aligned with said track anda doorway opening leading to said driveway,

a powered feed device carried by one side of the magazine structure andincluding a reciprocable plunger and a feed finger pivotally mountedthereon and operiable in the reciprocations of the plunger to engage thesuccessive shanks of fasteners to be driven to feed the same into saiddriveway,

said feed finger having a fastener shank engaging tip which is ofsubstantial width in a plane generally parallel to the axes of thefastener shanks to afford eficient thrust bearing along a substantiallength of the engaged shank,

said finger and plunger having opposed stop shoulders limitingarticulation of the finger relative to the plunger in one direction butpermitting articulation of the finger relative to the plunger in theopposite direction,

and guide surface means alongside said doorway and leading to saiddriveway for directing said finger in said one direction toward saidengagement of said stop shoulders and for guiding said tip positivelyand smoothly toward the driveway during feeding of a fastener into thedriveway by the finger.

References (Iited by the Examiner UNITED STATES PATENTS 2,078,064 4/1937Day l----53 2,707,277 5/ 1955 Aldrich 144.4 2,923,937 2/1960 Laucher144.4 2,979,725 4/1961 \Vandel et al. 144.4 X 3,099,837 8/1963 Heilmanet al. 1 -44.4

GRANVILLE Y. CUSTER, IR., Primary Examiner.

1. A FASTENER DRIVING MACHINE COMPRISING A BODY HAVING THEREIN ACOMPRESSED AIR RESERVOIR, A CYLINDER HAVING AN END EXPOSED TO THERESERVOIR AND A FIRST CONTROL VALVE FOR NORMALLY CLOSING SAID END OF THECYLINDER, A FASTENER DRIVER HAVING A PISTON RECIPROCABLE IN SAIDCLYINDER, MEANS FOR SUPPLYING FASTENERS INTO POSITION TO BE DRIVEN BYTHE DRIVER, PNEUMATICALLY OPERATED FEED MEANS MOUNTED ON THE MACHINE FORFEEDING THE FASTENERS INTO POSITION SUCCESSIVELY IN THE PATH OF THEDRIVER,